1. Field of the Invention
The present invention relates to a method for refreshing a flash memory of a cellular phone, more specifically, a method of directly refreshing a flash memory of a cellular phone with another cellular phone.
2. Description of the Prior Art
In recent years, the rapid development of wireless communications has made cellular phones indispensable products. As mobile communications enters the age of 3G, high-speed and wide-bandwidth wireless communications become a must of the cellular phone. Mobile computers, personal digital assistants (PDAs), and notebook PCs, requiring wide bandwidth, can wirelessly connect to the Internet by using cellular phones. Even cellular phones themselves have similar functions to PDAs and personal computers due to developments in technology such as small-size color liquid crystal displays (LCDs), low power consumption but high-performance system on chip (SOC) devices, and large-volume non-volatile flash memory chips.
Accordingly, present cellular phones not only receive and send signals but also have advanced functions such as displaying high-resolution photos and video games by using an LCD, connecting to the Internet to browse web pages, and playing various video and audio formats. Therefore, besides a embedded high-performance but low power consumption microprocessor, cellular phones further require large-volume memory for storing program codes and data to satisfy these functions.
However more software, programs, and data being stored inside cellular phones results in a need to update firmware, in order to correct programming errors and to support new functions provided by suppliers or designers. Therefore, before selling cellular phones or returning a cellular phone with updated firmware to a user, manufacturers and vendors have to update the program code and data stored in flash memory. In some cases, technicians have to reprogram the stored content in the flash memory for a malfunctioned cellular phone. Each above action requires a refresh of the flash memory of the cellular phone.
The conventional method for updating a flash memory of a cellular phone is to utilize a personal computer connected to a port of a cellular phone via an RS-232 transmission line to transmit and update data to the flash memory of the cellular phone. Please refer to FIG. 1. FIG. 1 is a schematic diagram of a conventional PC 10 refreshing a flash memory 16 of a cellular phone 12. An RS232 transmission port 11 of the PC 10 is connected with an earphone jack 13 of the cellular phone 12 through an RS232 transmission line 14. Because the operation voltage of the transmission port 11 is 7˜9 V and that of the earphone is 3.7V, no matter if the transmission signal is from the cellular phone 12 to the PC 10 or from the PC 10 to the cellular phone 12, the transmission signal has to be raised or reduced in voltage through a transformer 14 and then be sent.
Before transmitting data to the cellular phone 12, the PC 10 has to be installed with operation software, operating system (OS), and bin files to be transmitted to the flash memory 16 of the cellular phone 12. The user has to start the OS of the PC 10 so that the operation software is capable of being executed. Because the operation voltage and execution efficiency of the transmission port 11 are not the same as those of the earphone port 13, voltage-transformation and synchronization in communication protocols of the both ends are required before the synchronous transmission starts.
After setting synchronous transmitting, the operation software of the PC 10 sends a client program to a random access memory (RAM) 19 of the cellular phone 12 and then transmits the bin files to the flash memory 16. While transmitting the bin files to the flash memory 16, the PC 10 performs the following:
(a)The PC 10 continues to transmit the bin files to the flash memory 16 of the cellular phone 12 from the interruption of the previously transmitted bin files. Of course, if step (a) is executed for a first time, the transmission starts from the beginning of the bin files to the flash memory 16. The transmitted data from the PC 10 is first stored in a buffer 15 of the RAM 19 within the cellular phone 12 instead of being directly stored in the RAM 19 until the buffer 15 is filled.
(b)The cellular phone 12 writes fragments of the bin files in the buffer 15 into the flash memory 16 based on the formats of the bin files and addresses of the flash memory 16 accordingly. If the bin files have been transmitted completely after this step, the transmission action is ended; if only parts of the bin files have been transmitted, then repeat step (a).
If the highest baud rate available to RS-232 transmission line is 115200 bit/s (14.4 kByte/s), and a volume of the flash memory 16 is about 3 Mbytes, a total transmission time (excluding actually writing the bin files to the flash memory 16) is at least 200 seconds.
In addition, even though there are usually two transmission ports (such as serial ports) on the PC 10, the two ports typically share the same bandwidth (that is, 115200 bit/s). That means that if an operator wants to completely refresh two cellular phones 12 at the same time in the same PC, he cannot double the efficiency. And refreshing cellular phones via a number of computers results in excessive expense. Moreover, the refreshing action must be controlled by the PC 10, meaning that while refreshing a plurality of cellular phones, the PC 10 comparing to the cellular phones, consumes more energy and thus results in increasing costs. Meanwhile, during transmission by the serial port, if a bin file being transmitted is very large, the PC 10 can be too burdened to perform other programs. Hence, utilizing the prior art method to refresh a plurality of cellular phones leads to lower efficiency and higher cost.